Linear Technology LTC2450 User manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1067
EVALUATION BOARD
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LTC2450
DESCRIPTION
Demonstration circuit 1067 features the LTC2450, a
16 bit high performance ΔΣ analog-to-digital con-
verter (ADC). The LTC2450 features 2LSB linearity,
2LSB offset, and 1.4µV RMS noise. The input is sin-
gle ended with a range of 0 (Ground) to Vcc. The
modulator’s proprietary sampling technique reduces
the average input current to less than 50nA – orders
of magnitude lower than typical delta sigma ADCs.
The LTC2450 is available in a 6 pin, 3x3mm DFN
package and has an easy to use SPI interface.
DC1067 is a member of Linear Technology‘s
QuickEval™ family of demonstration boards. It is de-
signed to allow easy evaluation of the LTC2450 and
may be connected directly to the target application’s
analog signals while using the DC590 USB Serial
Controller board and supplied software to measure
performance. The exposed ground planes allow
proper grounding to prototype circuitry. After evaluat-
ing with Linear Technology’s software, the digital sig-
nals can be connected to the end application’s proc-
essor / controller for development of the serial inter-
face.
Design files for this circuit board are available. Call
the LTC factory.
LTC is a trademark of Linear Technology Corporation
Figure 1. Proper Measurement Equipment Setup
Ribbon cable
To DC590
Controller
Single-ended In-
put
Monitor reference / Vcc
or external reference
source (See Hardware
Set-u
p)

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1067
EVALUATION BOARD
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QUICK START PROCEDURE
Connect DC1067 to a DC590 USB Serial Controller
using the supplied 14 conductor ribbon cable. Con-
nect DC590 to host PC with a standard USB A/B ca-
ble. Run the evaluation software supplied with DC590
or downloaded from http://www.linear.com/software.
The correct program will be loaded automatically.
Click the COLLECT button to start reading the input
voltage. Details on software features are documented
in the control panel’s help menu.
Tools are available for logging data, changing refer-
ence voltage, changing the number of points in the
strip chart and histogram, and changing the number
of points averaged for the DVM display.
Figure 2. Software Screenshot

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1067
EVALUATION BOARD
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HARDWARE SET-UP
CONNECTION TO DC590 SERIAL CONTROLLER
J1 is the power and digital interface connector.
Connect to DC590 serial controller with supplied 14
conductor ribbon cable.
JUMPERS
JP1 – Select the source for REF+, either an LT6660-
5 or the regulated VCC voltage from the DC590
controller. Removing this jumper allows an external
supply to be connected to the VCC turret post.
ANALOG CONNECTIONS
Analog signal connections are made via the row of
turret posts along the edge of the board. Also, when
connecting the board to an existing circuit the ex-
posed ground planes along the edges of the board
may be used to form a solid connection between
grounds.
GND – Two ground turrets are connected directly to
the internal ground planes.
VCC – This is the supply and reference voltage for
the ADC. Do not draw any power from this point.
VIN – This is the single-ended input to the ADC.

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1067
EVALUATION BOARD
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